• 한국응용과학기술학회지
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• 제25권1호
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• pp.48-51
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• 2008

Dipalmitoyl phosphatidyl choline and p-nitrophenyl palmitate were directly sonicated in acidic water for 6 minutes to give clear stock solutions. The catalytic hydrolysis of p-nitrophenyl palmitate was studied at $30-50^{\circ}C$ in the presence of unilamellar vesicle and mixture of unilamellar and multilamellar aggregates. The difference of reaction rate between unilamellar and multilamellar was observed. The rate of unilamellar reaction compared to the rate of mixture reaction showed more catalytic effect. The phase transition temperature of vesicle was measured at $37-44^{\circ}C$.

• 전기화학회지
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• 제13권4호
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• pp.240-245
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• 2010

This work explored the catalytic effect of Pt in multi-wall carbon nanotube and poly-pyrrole conductive polymer electrocatalysts (Pt/PPy/MWCNT). A home-made Pt/PPy/MWCNT catalyst was first evaluated by comparing its electrochemical active surface area (ESA) with E-Tek commercial catalysts by cyclic voltammetry in $H_2SO_4$ solution. Then, the methanol oxidation currents of Pt/PPy/MWCNT and the hydrogen peaks in $H_2SO_4$ solution were serially measured with microporous electrode. This provided the current density of methanol oxidation based on the ESA, allowing a quantitative comparison of catalytic activity. The current densities were also measured for Pt/C catalysts of E-Tek and Tanaka Precious Metal Co. The current densities for the different catalysts were similar, implying that catalytic activity depended directly on the ESA rather than charge transfer or electronic conductivity.

• 한국대기환경학회지
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• 제20권5호
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• pp.663-670
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• 2004

The catalytic oxidation of benzene, toluene and xylene over a spent industrial catalyst (Pd-based) was investigated in a fixed bed flow reactor system. According to the priming condition, the properties of a spent Pd-based catalyst were characterized by XRD(X-ray diffraction). BET(Brunauer-Emmett-Teller) and ICP(Inductively coupled plasma). When air was used as a primer, optimum priming temperature was found to be 200$^{\circ}C$, and the catalytic activity decreased as the priming temperature increased. When a spent Pd-based catalyst primed with air at 200$^{\circ}C$ was re-treated with hydrogen at 200$^{\circ}C$, 300$^{\circ}C$ or 400$^{\circ}C$, respectively, the catalytic activity increased and thermal effect were negligible. $HNO_3$ aqueous solution priming resulted in slight decrease of the catalytic activity, with little effects on $HNO_3$ concentrations. The activity of a spent Pd-based catalyst with respect to VOC molecule was observed to follow sequence: xylene> toluene> benzene. Benzene. toluene and xylene could be removed to almost 100% by a spent Pd-based catalyst primed with hydrogen.

• 한국산업융합학회 논문집
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• 제9권1호
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• pp.13-19
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• 2006

The ozone produced by a dielectric barrier discharge device was injected into the exhaust gas to oxidize a part of NO to $NO_2$, and then the exhaust gas containing the mixture of NO and $NO_2$ was further treated in a catalytic reactor where both NO and $NO_2$ were reduced to $N_2$ in the presence of ammonia as the reducing agent. The $NO_2$ content in the mixture of NO and $NO_2$ was changed by the amount of ozone added to the exhaust gas. The experiments were primarily concerned with the effect of reaction temperature on the catalytic $NO_x$ reduction at various $NO_2$ contents. The increase in the $NO_2$ content by the ozone injection remarkably improved the performance of the catalytic $NO_x$ reduction, especially at low temperatures.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.267-267
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• 2012

$TiO_2$-Ni inverse catalysts were prepared using atomic layer deposition (ALD) process and catalytic $CO_2$ reforming of methane (CRM) reaction over catalysts (either bare Ni or $TiO_2$ coated-Ni particles) were performed using a continuous flow reactor at $800^{\circ}C$. $TiO_2$-Ni inverse catalyst showed higher catalytic reactivity at initial stage of CRM reactions at $800^{\circ}C$ comparing to bare Ni catalysts. Moreover, catalytic activity of $TiO_2$/Ni catalyst was kept high during 13 hrs of the CRM reactions at $800^{\circ}C$, whereas deactivation of bare Ni surface was started within 1hr under same conditions. The results of surface analysis using SEM, XPS, and Raman showed that deposition of graphitic carbon was effectively suppressed in a presence of $TiO_2$ nanoparticles on Ni surface, thereby improving catalytic reactivity and stability of $TiO_2$/Ni catalytic systems. We suggest that utilizing decoration effect of metal catalyst with oxide nanoaprticles is of great potential to develop metal-based catalysts with high stability and reactivity.

• 한국분말재료학회지
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• 제8권3호
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• pp.197-200
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• 2001

Modified inert gas condensation method was used to produce the nanocluster composites of $CuO/CeO_2$. High-resolution TEM, SEM and catalytic measurements have been used to characterize the samples and study the synergistic effect between the CuO phase and $CeO_2$(ceria) support. By varying the He pressure, the heating temperature and configuration of the heating boats inside the modified gas condensation chamber, nanoclusters of varying sizes, shapes and composition can be produced. The composition and nanostructured morphology were shown to influence the catalytic properties of the system. A copper content around 10 at% with a morphology that favors high-energy surfaces of ceria is shown to be beneficial for a high catalytic activity.

• 대한기계학회논문집B
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• 제23권7호
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• pp.841-855
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• 1999

In the present work, the effect of a flow maldistribution on the thermal and conversion response of 8 monolith catalytic converter is Investigated. To achieve this goal, a combined chemical reaction and multi-dimensional fluid dynamic mathematical model has been developed. The present results show that flow uniformity within the monolith brick has 8 great impact on light-off performance of the catalytic converter. In the case of lower flow uniformity, large portions of the monolith remain cold due to locally concentrated high velocities and CO, HC are unconverted during warm-up period, which loads to retardation of light-off. It has been also found that the heat-up pattern of the monolith ill similar to the flow distribution profile, In the early stage of the reaction. It may be concluded that flow maldistribution can cause a significant retardation of the light-off and hence can eventually worsen tho conversion efficiency of automotive catalytic converter.

• Bulletin of the Korean Chemical Society
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• 제25권9호
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• pp.1355-1360
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• 2004

The oxidative decomposition of trichloroethylene (TCE) was investigated using palladium catalysts supported on pure and sulfated zirconia. The reactions were performed under dry and wet conditions in the temperature between 200 and $550^{\circ}C$ keeping GHSV of 14,000 $h^{-1}.$ The products such as $C_2Cl_4,\;C_2HCl_5,\;CO\;and\;CO_2$ were observed in the reaction. The addition of water in the feed affected the distribution of reaction product with dramatically improved catalytic activity. The spectroscopic investigations gave an evidence that the strong acid sites play an important role on controlling the catalytic activity. Among the catalysts investigated, the Pd-loaded sulfated zirconia catalyst with 1 wt% Pd was found to exhibit the highest catalytic activity in the presence of water vapor having the stability for 30 h of the reaction at $500^{\circ}C$. The successful performance of the catalyst might be attributed to promotional effect of Pd active sites and strong acid sites induced from surface sulfate species on zirconia.

• 한국수소및신에너지학회논문집
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• 제33권1호
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• pp.105-112
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• 2022

Copper (Cu)-based catalysts have been widely used in a methanol steam reforming (MSR) reaction for hydrogen production for air-independent propulsion (AIP) applications and their good catalytic activities have attracted much attention. However, the agglomeration of the catalytic active site Cu causes deteriorating the catalytic performance and suppression of Cu agglomeration is a crucial issue in the AIP applications that the MSR system is typically operated at 250-300℃ for a long time. R. Sakai et al. recently showed a computational study on the anchoring effect that reduces an agglomeration of active sites by doping in a supporter. In order to present the anchoring effect on 𝛾-Al₂O₃ supported Cu-based catalysts, in this study, the adsorption energies of Cu on X-doped (X=ruthenium, phosphorus, silicon) 𝛾-Al₂O₃ were calculated and Cu adsorption energy decreased due to a change of the electronic structure originated from doping, thereby proving the anchoring effect.

• 청정기술
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• 제6권1호
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• pp.17-25
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• 2000

상압유통식 고정층반응기를 이용하여 전이금속을 ALO-6에 담지한 촉매상에서 휘발성유기화합물인 벤젠, 톨루엔, 자일렌의 촉매산화에 관하여 조사하였다. 15% 전이금속/ALO-6 촉매상에서 톨루엔의 완전산화반응에 대한 활성의 크기는 Cu>Mn>Fe>V>Mo>Co>Ni>Zn의 순서였다. 15% Cu/ALO-6 촉매에서 소성온도의 증가는 비표면적을 감소시켰고 결과적으로 활성은 감소하였다. Cu/ALO-6촉매계에서 Cu의 담지량이 5%일 때 활성이 우수하였다. 5% Cu/ALO-6촉매상에서 벤젠, 톨루엔, 자일렌은 반응온도 $380^{\circ}C$, 접촉시간 4.5 g-cat.hr./g-mole 이상일 때 이산화탄소로 완전산화 되었다. 반응물에 따른 활성순서는 톨루엔>자일렌>벤젠 이었다. 반응물의 농도가 증가함에 따라 self-poison 에 기인하여 활성은 감소하였다.